Keston Boiler Error Codes: Pressure, Ignition & Temperature Faults Explained

Keston Boiler Fault Codes Overview

Keston produces premium boilers popular in London's luxury properties. While Keston systems are known for reliability, when faults do occur, understanding the fault code is the first step toward resolution.

Common Keston Fault Codes

Pressure Faults

Code 02 or 03: Pressure Loss

These codes indicate system pressure has fallen below safe operating range. Causes include:

• Natural pressure loss from temperature changes
• Slow leak in pipework or radiator connections
• Failed expansion vessel
• Faulty pressure relief valve

Fix: Re-pressurize using the filling loop. If pressure drops again within weeks, you have a leak that needs professional detection.

Ignition Faults

Code 30: Ignition Failure

Your Keston boiler cannot ignite. Possible causes:

• Gas supply turned off at meter or isolation valve
• Ignition electrode contaminated or damaged
• Faulty spark generator
• Gas valve electrical fault

Fix: Check gas supply first. If gas is on, the ignition electrode usually needs cleaning or replacement. This is a quick fix for our engineers.

Temperature Faults

Code 05 or 07: Overheating

Your boiler has reached dangerous temperatures. This usually indicates:

• Blockage in heat exchanger from sludge/scale
• Faulty temperature sensor
• Failed circulation pump
• System overpressurized

Fix: Do NOT restart repeatedly. Call an engineer for diagnosis. A power flush often resolves this if sludge is the cause.

Sensor Faults

Code 08 or 09: Sensor Malfunction

Temperature, pressure, or flame sensors have failed. These require replacement as they cannot be repaired.

Keston Boiler Maintenance Tips

Most Keston fault codes can be prevented with proper maintenance:

• Annual servicing: Engineers check sensors, clean electrodes, inspect for leaks
• Power flushing: Removes sludge that causes overheating and pressure issues
• Inhibitor treatment: Adds corrosion inhibitor to prevent magnetite buildup
• Magnetic filter installation: Catches corrosion particles before they damage seals

When to Call an Engineer

If you see any of these codes on your Keston boiler, contact RARE immediately:

• Any error code that won't clear after one reset attempt
• Codes that recur within days or weeks
• Pressure loss that requires re-pressurizing every month
• Any overheating codes (05, 07)

Why RARE for Keston Repairs

Keston boilers require specialist knowledge:

• We stock Keston-specific parts on our vans
• Our engineers trained extensively on premium Keston systems
• Same-day diagnosis and repair in most cases
• Full warranty preservation through Gas Safe compliance
• 24/7 emergency response across London

Don't guess at fault codes — proper diagnosis saves money and prevents damage.

Book a Keston Engineer

For any Keston fault code, RARE's Gas Safe engineers are available 24/7 across London. We'll identify the root cause and fix it with transparent pricing and no surprises.